06X6spdGTO

iTrader: (6)

Have a friend putting together a 408 LQ4, we r wondering what everyone thinks it will put down, anyone have any tips or suggestions on the build itself?

Details: 408LQ4 Mahle -12cc dish pistons (.020 above deck), 10.9:1 SCR,
PRC Stg 2.5 Ls6 heads, 64cc chambers .660 dual springs,
kooks 1.75" LTs,
TSP True Duals,
Catless, 42lb green top SVO injectors
gm mls headgasket
K1 6.125 rods
K1 4" crank
242/246 .612 .614 113 + 2
Ls7 Lifters
Tsp Oil pump
Asp 25% UD
Monster Stg 3 Clutch and flywheel kit
moser 12bolt 4:10s
Fast 90/90
Volant Twin cone Fbody CAI
85mm Maf
Steel DS

Car is a 2001 M6 WS6, will be dynoed on a dynojet 248h. Dyno is a bit tough, G6x3 cam, 1.875" Kooks, o/r xpipe, Ud pulley, fast 102, cold air induction CAI, M6 2010 LS3 Camaro put down 483/445wtq on same dyno.

Hes hoping for 525ish whp/490wtq


Other cars that have dynoed @ the same shop:
WWW.DYNOSPORT.COM

mark21742

Looks pretty good, personally I ditched my MAF in favor for an SD tune, and went with a 255/263 .634/.624 115lsa cam. You would be suprised st how much duration the larger cubes eat up and tame down.

black00ssFL

iTrader: (24)

I'm gonna guess 480-490hp. That's not quite enough cam/compression/heads to reach 525rwhp IMO. But hey, I could be wrong.

Also, there's a whole section dedicated to dyno guessing and bench racing

https://ls1tech.com/forums/dyno-gues...ing-forum-150/

06X6spdGTO

iTrader: (6)

Kinda looking for more than just guesses here, really appreciate others feed back on what the weak parts of the build are.

Still wanting a streetable car so didnt go bat **** crazy with it. Figured the cam posted with a little larger LSA, but appreciate the suggestions!

66LeMans

Mid 480s hp and around 470 tq. Gonna be interesting to see what it makes.

Sales@Tick

iTrader: (3)

Have almost the same build except my cam is bigger but I have lower compression (300 shot)... and mine made 487rwhp on motor through 1 3/4 headers and catted y pipe. I put 1 7/8 and TSP true dual now but havent had it dynoed again.

06X6spdGTO

iTrader: (6)

^ what kind of cam specs are you running if you dont mind sharing??

Sales@Tick

iTrader: (3)

248/256 .615/.622 113 lsa
and i have the ls6 stage 3 heads
and Fast 92/92

Its going to depend alot on your compression that you end up running. I have 10:1 with -10cc pistons. If you bump to 11.5:1 or even 12:1 you could make 520-540rwhp I would think.

06X6spdGTO

iTrader: (6)

With the 12cc dish mahle and 64cc heads I think we are hard pressed to get to the 11.5:1 and higher SCR. Heck the pistons are already around :020 to :025 above deck! Tried talking him into going with the 8cc dish pistons from weisco but he didnt want to spend the extra 125-150 bucks for them. Should be around 10.9:1 SCR

06X6spdGTO

iTrader: (6)

I your opinon chris how do the prc 2.5 ls6 heads compare to the stage 3 prc LS6 heads on the 408?

black00ssFL

iTrader: (24)

I think it'd still be pretty drivable with a bigger cam.

How about milling the heads? I'm showing 11.1:1 as it sits. If you can get the heads to 61cc that gives 11.5:1

ZGLASS

iTrader: (11)

Yea I'm thinking 480-490 and 465-475tq. Those heads are just not enough for a 408.

06X6spdGTO

iTrader: (6)

Well the heads were to get milled down farther, I think it would be losing some Flow for Compression. Another thing is how much PTV we would still have. It should have enough room with the dished pistons but Im sure we would want to check first.

Im guessing a upgraded set of PRC Stg 3 LS6 heads slightly milled and a little bigger stick (246/253 .62x .62x 112LSA) would be a nice upgrade for him down the road. would be nice to convince him to go with a set of TFS or AFR's!!

Sales@Tick

iTrader: (3)

Stage 3s for sure... however the ls6 heads just cant flow enough for these motors... I would like to get a set of trickflow 235s

01ssreda4

iTrader: (96)

Take it with a grain of salt, this is the internet. I think it looks like a strong combination of parts for the money invested......however, I would ditch the (I presume) stock steel DS in favor of an aftermarket unit, and like already stated consider a SD tune. 1 7/8 th headers may benefit some on this combo as well. We are just trying to help you. If you want semi-exact numbers, nobody can give them to you, but some digging on your part may yield some numbers on some very similar combos.

ringram

+1 Get some better heads

06X6spdGTO

iTrader: (6)

I understand this is the interwebs just seeing if everyones on the same page so r expectations arent too high, and some insight on the areas we have to improve on.

sscamaroburn02

iTrader: (14)

I don't think you will hit 500hp. With better heads you should easily, raise that compression up a bit if it was me.

06X6spdGTO

iTrader: (6)

Biggest problem on too much compression is around here we only have 91octane, unless you plan to do E85.

sscamaroburn02

iTrader: (14)

good point. I just take for granted our 93 octane here. It's everywhere.